A septate uterus is a congenital uterine anomaly where the uterus is divided by a wall of tissue, known as a septum, which can extend partially or completely down the middle of the uterine cavity. This condition develops during fetal growth. This article explores the developmental processes leading to its formation.
Understanding Uterine Formation
The female reproductive system, including the uterus, develops from two structures called Müllerian ducts. These paired ducts begin to form around the sixth week of embryonic development. They grow and eventually fuse together in the midline, forming the structures that will become the upper two-thirds of the vagina, the cervix, the uterus, and the fallopian tubes.
The fusion of the lower parts of these Müllerian ducts occurs between the seventh and ninth weeks of gestation. This fusion process initially creates a central wall or septum within the newly formed uterine cavity. Normally, this midline septum then undergoes a process of resorption, where the tissue is absorbed by the body, leading to a single, hollow uterine cavity. This resorption process typically completes by around the 20th week of embryonic development.
The Developmental Anomaly
A septate uterus arises when the normal process of septum resorption is incomplete. Instead of the central wall being fully absorbed, a remnant of this tissue persists, dividing the uterine cavity into two compartments. This developmental disruption happens during fetal development.
The extent of the septum can vary, ranging from a partial division that does not reach the cervix to a complete septum that extends all the way to the cervix and, in some cases, even into the vagina. The septum itself can be composed of fibrous tissue, muscular tissue, or a combination of both. While the exact mechanism for this failure of resorption is not fully understood, it is considered a spontaneous developmental error in the programmed regression of tissue.
Factors Not Implicated in Causation
A septate uterus is generally considered a spontaneous developmental anomaly, meaning it occurs without a clear external cause. This condition is not typically passed down through families, as a direct genetic inheritance pattern has not been established.
Lifestyle choices made by the mother during pregnancy, such as diet or activity levels, are not known to cause a septate uterus. Environmental factors, like exposure to toxins or most medications, are also not considered primary causes of this uterine anomaly. While some research mentions potential links between certain environmental factors or specific historical drug exposures (like diethylstilbestrol) and uterine anomalies, these are not established as common causes for septate uterus.